//
// main.cpp
//
// exercise solution - chapter 7
// modern cpp tutorial
//
// created by changkun at changkun.de
// https://github.com/changkun/modern-cpp-tutorial/
//

#include <chrono>    // std::chrono::seconds
#include <future>    // std::future
#include <iostream>  // std::cout, std::endl
#include <string>    // std::string
#include <thread>    // std::this_thread::sleep_for
#include <vector>    // std::vector

#include "thread_pool.hpp"

int main() {
  // create a thread pool with max. 4 concurrency threads
  ThreadPool pool(4);
  // create execution results list
  std::vector<std::future<std::string> > results;

  // start eight thread task
  for (int i = 0; i < 8; ++i) {
    // add all task to result list
    results.emplace_back(
        // ass print task to thread pool
        pool.enqueue([i] {
          std::cout << "hello " << i << std::endl;
          // wait a sec when the previous line is out
          std::this_thread::sleep_for(std::chrono::seconds(1));
          // keep output and return the status of execution
          std::cout << "world " << i << std::endl;
          return std::string("---thread ") + std::to_string(i) +
                 std::string(" finished.---");
        }));
  }

  // outputs
  for (auto&& result : results) std::cout << result.get() << ' ';
  std::cout << std::endl;

  return 0;
}